<template>
  <div class="goods-image">
    <!-- 左边大图片可放大 -->
    <div class="large" v-if="show" :style="[{ backgroundImage: `url(${images[currIndex]})` }, bgPosition]"></div>
    <!-- 浏览图片 -->
    <div class="middle" ref="target">
      <img alt="" :src="images[currIndex]">
      <!-- 遮罩层 -->
      <div class="layer" v-if="show" :style="position"></div>
    </div>
    <!-- 右边切换图片 -->
    <ul class="small">
      <li v-for="(img, i) in images" :key="img" :class="{ active: i === currIndex }">
        <img :src="img" alt="" @mouseenter="currIndex = i">
      </li>
    </ul>
  </div>
</template>
<script lang="ts" setup>
// 商品详情图片放大组件
import { ref, reactive, watch } from 'vue'
import { useMouseInElement } from '@vueuse/core'
const props = defineProps({
  // 存放使用者传来的图片
  images: {
    type: Array,
    default: () => []
  },
})
const images = props.images as []
// 自定义图片一个下标,来控制图片的查看
const currIndex = ref(0)
// 拿到控制的标签元素
const target = ref(null)
// 控制是否进入图片预留显示放大图片和遮罩层
const show = ref(false)
// 鼠标基于图片容器偏移(遮罩层)
const position: any = reactive({ left: 0, top: 0 })
// 鼠标基于图片容器偏移带动放大图片容器偏移量
const bgPosition: any = reactive({ backgroundPositionX: 0, backgroundPositionY: 0 })
// 拿到容器的偏移量useMouseInElement(控制的元素标签)
// elementX 鼠标基于容器左上角X轴偏移
// elementY 鼠标基于容器左上角Y轴偏移
// isOutside 鼠标是否在模板容器外
const { elementX, elementY, isOutside } = useMouseInElement(target)
// 监听elementX, elementY, isOutside的变化驱动视图
watch([elementX, elementY, isOutside], () => {
  // 控制X轴方向的定位 0-200 之间
  // 左边 
  if (elementX.value < 100) {
    position.left = 0
    position.top = 0
    // 右边
  } else if (elementX.value > 300) {
    position.left = 200
    position.top = 0
  } else {
    // elementX.value - 100鼠标会在遮罩层中间
    position.left = elementX.value - 100
  }
  // 控制Y轴方向的定位 0-200 之间
  // 上边
  if (elementY.value < 100) {
    position.top = 0
    // 下边
  } else if (elementY.value > 300) {
    position.top = 200
  } else {
    position.top = elementY.value - 100
  }
  // 设置放大图片背景的定位
  bgPosition.backgroundPositionX = -position.left * 2 + 'px'
  bgPosition.backgroundPositionY = -position.top * 2 + 'px'
  // 设置遮罩容器的定位
  position.left = position.left + 'px'
  position.top = position.top + 'px'
  // 设置是否显示预览大图
  show.value = !isOutside.value
})
</script>
<style  lang="less" scoped>
@import '../../assets/styles/mixins.less';
@import '../../assets/styles/variables.less';

.goods-image {
  position: relative;
  display: flex;
  width: 480px;
  height: 400px;
  z-index: 500;

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move;

    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, .2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>